Honestly, I dislike the double sided cards entirely since they're a hassle to keep flipping as needed. Adventures, Kamigawa flips, split cards, all of those are much more user friendly than double sided stuff. I use double sided stuff about as much as I always have, which is to say as little as possible.
That said, I do end up using a few of them just because they're powerful enough to be needed even with the frustration of their use or I never end up needing to flip them. I have two different copies of
Ayara, Widow of the Realm sleeved up for her deck, one for each side, a couple different pathways that almost never get flipped and even if they do I don't generally need to reflip them when they do,
Flamescroll Celebrant for Winota,
Poppet Stitcher for Wilhelt combos, and a few good battles like
Invasion of Karsus in
Neera, Wild Mage for example giving me a
Guttersnipe without it being a creature while in the deck to avoid interfering with polymorphing tokens into
Displacer Kitten.